Gas chromatograph (GC) columns are usually identified by a metal tag fastened to the column basket or holder. These tags list the column part number, serial number, size and information about the phase, type and thickness. For standard GC columns, these tags are in the oven with the column and so are not readable unless the column oven door is opened. For a new type of column, a Low Thermal Mass or LTM column, the tag is fastened to a cover around the column, but this may be hidden by a protective cover during use,
While the tags attached to columns may contain all of the information needed to operate the columns in the instruments in which they are installed, the information on the tags must be manually entered into the GC or an interfaced computer in order to make use of the information.